EasyDriver V4.4, connecting STEP and DIR

Robotics
1

Hi - I can’t find a definitive answer to this online. Perhaps it’s too obvious…!

For an experimenting board, I want to drive STEP and DIR from push microswitches (hoping there’s debounce?).

I’m used to tying inputs high with 10K’s and taking them to ground as needed, but the schematics online show a variety of methods, some with resistors going both up and down! Some say that on later versions there are 20K pullups on those inputs. Does that mean I can just switch them to ground?

I want to get it right, as I’ve also read that incorrectly driving DIR can cause overheating.

What method should I use?

Thank-you,

2

There are pull down resistors for STEP and DIR, you only need a switch to connect each pin to VCC to activate either.

DIR can be a simple toggle switch and step should be a momentary button.

There is no deboucing built into the EasyDriver, you’d need to do that externally if switch bounce is a problem :slight_smile:

3

Right, thanks a lot.

Isn’t having pull-DOWN resistors a bit unusual? I feel nervous connecting inputs straight to Vcc, rather than ground.

(I haven’t looked for a schematic yet. Is it available?)

4

The schematic is at http://www.schmalzhaus.com/EasyDriver/E … 44_sch.pdf

It looks like V4.4 doesn’t have pullups or pulldowns on step and dir (unless they are enabled on chip). V4.5 has a pulldown and a series resistor, so you need to be careful using a pullup as well as you will be creating a voltage divider…

/mike

5

Are you using SparkFun’s version or another version? We can only provide support for the SparkFun version.